Biomedical subjects

H W Ackermann

Publications and source records attributed to H W Ackermann.

At least 37 records · Page 2Linked to original sources

PubMed1992

Frequency of morphological phage descriptions.

Bacteriophages are listed by morphotypes and host genera. At least 4.007 phages, belonging to 13 virus families, have been described since 1960. About 3,850 phages (96%) are tailed and 154 phages (4%) are cubic, filamentous, or pleomorphic. Siphoviridae or phages with long noncontractile tails constitute 60% of tailed phages. Phages are found in over 100 bacterial genera including archaebacteria and rickettsiae. Their distribution is very uneven and probably reflects the evolutionary history of bacteria.

Bacteria↗

PubMed1992

The species concept and its application to tailed phages.

A recently proposed polythetic definition of virus species appears easily applicable to bacteriophages. Criteria for classification of tailed phages are evaluated. Morphology, DNA homology, and serology are the most important criteria for delineation of species, but no single criterion is satisfactory. Dot-blot hybridization and seroneutralization may suggest false relationships by detecting common sequences in the DNA of otherwise unrelated phages. Species of tailed phages can be defined by a combination of morphology and DNA homology or serology. A procedure for identification of novel phages is outlined. Phage names should include elements of host names.

Bacteriophages↗

PubMed1992

Characteristics and diffusion in the rabbit of a phage for Escherichia coli 0103. Attempts to use this phage for therapy.

A bacteriophage for Escherichia coli 0103 was isolated during a study on E. coli diarrhoea in intensive breeding units of rabbits. The phage had an isometric head and a short tail and resembled coliphage N4 (Podoviridae). It had a very narrow host range and seemed to be specific for serogroup 0103, suggesting that it might be used for preliminary identification of E. coli strains of this serogroup instead of the usual slide agglutination. In view of its possible use as a therapeutic phage, we investigated its dissemination in rabbit organs after oral administration. The phage persisted in the spleen for at least 12 days. However, in vivo studies showed that this phage and a mixture of more virulent phages for E. coli 0103 were ineffective in preventing disease in rabbits inoculated with an enteropathogenic strain of E. coli 0103.

Animals↗

PubMed1992

Large-scale blood substitute production using a microfluidizer.

Microfluidization has been tested as a way to disperse phospholipids in aqueous hemoglobin solutions. Spherical and stable liposomes of 2 to 3 microns were obtained. Lipid incorporation (up to 85%) and hemoglobin encapsulation (up to 15%) in liposomes have been improved with respect to previous investigations. However, results show that a more efficient dispersion system using lower concentrations of lipid is required to obtain a high liposome hemoglobin concentration (limited actually to 150 g/l) and an economically and biologically suitable process for artificial blood production at large scale.

Blood Substitutes↗

PubMed1989

A new bacteriophage of Corynebacterium glutamicum isolated from swine waste.

A bacteriophage for Corynebacterium glutamicum strain LP-6 was isolated from swine waste. It belongs to the Siphoviridae family or Bradley morphologic group B, has a narrow host range, and is sensitive to chloroform and resistant to carbon tetrachloride. The phage is unstable (96% inactivation) in swine waste stored for 4 months at 22 C. The DNA has a molecular weight of approximately 20 Md, cohesive ends, and numerous restriction endonuclease sites. The phage differs from other known C glutamicum phages.

Animals↗

PubMed1988

Morphology of Brochothrix thermosphacta phages.

Twenty-one Brochothrix thermosphacta phages were examined by electron microscopy. They had isometric heads and contractile or long and noncontractile tails, and were grouped into three species belonging to the Myoviridae (species A19) or Siphoviridae (species NF5 and BL3) families of tailed phages. Species A19 has highly characteristic morphological features and resembles well-known phages of Bacillus, Lactobacillus, Staphylococcus and Streptococcus, indicating phylogenetic relationships between these phages as well as their hosts.

Bacteriophages↗

PubMed1987

Bacteriophage taxonomy in 1987.

Ten families and eight genera have been approved by the International Committee on Taxonomy of Viruses (ICTV) and include at least 230 species. A new basic phage group has been found in Archaebacteria. Over 2700 phages are tailed; about 130 are cubic, filamentous or pleomorphic. Their distribution provides insights into phage origin.

Bacteriophages↗

PubMed1985

New actinophage species.

All actinophages of known morphology are tailed. From 305 phages surveyed, 4 belong to the Myoviridae family, 283 to the Siphoviridae, and 18 to the Podoviridae (two morphotypes each). 58 of 139 actinophages described since 1976 are classified in this report, and the earlier phage descriptions are updated. Nine new species and type viruses are proposed, bringing the total number of actinophage species to 29 and the number of bacterial host genera to 15.

Actinomycetales↗

PubMed1985

[Morphology of new Listeria phages].

Seventeen Listeria phages have isometric heads and long, noncontractile tails. Twelve of them belong to three already known phage species. Five phages represent a new species, named H387.

Bacteriophages↗

PubMed1984

Morphology of Pasteurella multocida bacteriophages.

Twenty-one tailed phages with icosahedral heads belong to the Myoviridae, Siphoviridae, and Podoviridae families and to four morphological types. Type AU, with 10 phages, has a contractile tail and is morphologically identical with coliphage P2. Lysates contain contracted tail sheaths assembled end-to-end and abnormal structures with long tails and multiple tail sheaths. Types C-2 and 32, with one and three phages, respectively, have long, noncontractile tails. Type 22 includes seven phages, has a short tail, and resembles coliphage T7. Our results agree with previous biological data and suggest that types AU, C-2, 32, and 22 correspond to four different phage species.

Bacteriophages↗

PubMed1984

Six groups of double-stranded RNA mycoviruses.

Six groups of double-stranded (ds) RNA mycoviruses have been proposed. The main characteristics which define a group are described, and the properties of members and probable members of each group are tabulated. Possibilities for organization of the groups into families, genera and species are discussed. The classification scheme could ultimately accommodate the majority of the well-characterized dsRNA mycoviruses.

Fungi↗

PubMed1984

Classification of Vibrio bacteriophages.

85 Vibrio phages, 84 of them tailed and 1 filamentous, were surveyed. The tailed phages belonged to six basic morphotypes and to the Myoviridae, Siphoviridae, or Podoviridae families. 63 phages were classified into 18 species. The filamentous phage is a member of the Inovirus genus of the Inoviridae family. Vibrio phages are very heterogenous and include some morphologically interesting viruses. Several Vibrio phages closely resemble phages of other gram-negative bacteria, possibly indicating phylogenetic relationships between their hosts.

Bacteriophages↗

PubMed1984

New species definitions in phages of gram-positive cocci.

About 290 phages of the bacterial genera Leuconostoc, Micrococcus, Staphylococcus, and Streptococcus were surveyed. The phages belong to the Myoviridae, Siphoviridae, and Podoviridae families and comprise seven basic morphotypes. Fourteen new species are proposed, bringing the number of phage species for gram-positive cocci to 27. The distribution of particular phage types may indicate phylogenetic relationships between host bacteria.

Bacteriophages↗

PubMed1983

Sewage coliphages studied by electron microscopy.

Sewage was enriched with 35 Escherichia coli strains, and sediments of enrichment cultures were studied in the electron microscope. They contained up to 10 varieties of morphologically different particles. T-even-type phages predominated in 14 samples. Thirteen phages were enriched, representing the families Myoviridae (seven), Styloviridae (two), Podoviridae (three), and Microviridae (one). Twelve of these corresponded to known enterobacterial phage species, namely, 121, K19, FC3-9, O1, 9266, T2, 16-19, kappa, beta 4, N4, T7, and phi X174. Cubic RNA phages and filamentous phages were not detected. Types 121 and 9266 have previously been observed only in Romania and South Africa. Identification by morphology is usually simple. Our investigative technique is qualitative and will not detect all phages present. Most enrichment strains are polyvalent, and electron microscopy is always required for phage identification. In a general way, electron microscopy seems to be the method of choice for investigation of phage geography and ecology.

Coliphages↗

PubMed1982